Summary:
Pyrimidine, purine, and pyridine nucleotide synthesis all require phosphoribosylpyrophosphate (PRPP) as a precursor. PRPP is utilized by both the de novo pathways and the auxiliary or salvage pathways by which endogenously formed or exogenously added pyrimidine, purine, or pyridine bases are converted to the corresponding ribonucleoside monophosphates by phosphoribosyltransferases. PRPP is also used in the histidine and tryptophan biosynthesis pathways. PRPP thus may be regarded as a precursor for the synthesis of nucleic acids, proteins, and for the NAD(P) coenzymes.The formation of PRPP therefore is subjected to strict metabolic control. [HoveJensen86]